I believe that this could easily be organised, however, it may take a few trials first. We would have to see if it was more beneficial to hire per load, per person (follow the same guy around carrying his loads back for profits) or something similar. Personally, I often hire messengers to carry small items and messages to others. While I have a large choice of 'assistants' to work with it isn't to hard to find one. Also, how someone would contact the service would be hard to arrange. If it is a guild then it will be hard to recruit members other the new players. More experience players prefer guilds for different purposes, so they wouldn't need to do it for money. Of course, a stroke of luck may land a courier a routine job such as taking supplies from Hydlaa to Oja, or to deliver newspapers to better selling points.
In short, a good idea if organized correctly. If you do plan to go ahead with this idea then please contact me as this service would be of great use to me.